Liu Chunyan, Hao Yanan, Yin Fei, Zhang Yonglan, Liu Jianhui
Chongqing Key Lab of Medicinal Chemistry and Molecular Pharmacology, Chongqing University of Technology, Chongqing, 400054, China.
Cell Biol Int. 2017 May;41(5):544-554. doi: 10.1002/cbin.10758. Epub 2017 Apr 4.
Our previous works indicated that geniposide could regulate glucose-stimulated insulin secretion (GSIS), and improved chronic high glucose-induced dysfunctions in pancreatic β cells, but the molecular mechanisms remain largely unknown. In the present study, we investigated the role of 5'-AMP-activated protein kinase (AMPK) in high glucose induced cell injury and explored the associated molecular mechanisms in rat INS-1 pancreatic β cells. Data suggested that geniposide obviously prevented the cell damage induced by high (25 mM) glucose in INS-1 cells, which increased the protein levels of cell apoptosis-associated enzymes, including heme oxygenase-1 (HO-1), and Bcl-2, but apparently attenuated the protein level of Bax, an apoptotic protein. In addition, Compound C, an AMPK inhibitor, remarkably inhibited the effects of geniposide on the protein levels of HO-1, Bcl-2, and Bax, but AICAR, an AMPK activator, potentiated the role of geniposide on the protein levels of HO-1, Bcl-2, and Bax. More importantly, geniposide directly prevented the cleavage of caspase-3 induced by high glucose, and this effect was also evidently prohibited by the pre-incubation of compound C in high glucose-treated INS-1 cells. Furthermore, using the method of RNA interfere, we further proved that treatment with AMPK siRNA attenuated the effects of geniposide on the apoptosis-associated proteins and cell viability. All these data suggest that AMPK plays a crucial role on geniposide antagonizing high glucose-induced pancreatic β cells injury.
我们之前的研究表明，栀子苷可以调节葡萄糖刺激的胰岛素分泌（GSIS），并改善慢性高糖诱导的胰腺β细胞功能障碍，但其分子机制仍 largely 未知。在本研究中，我们研究了 5'-AMP 激活蛋白激酶（AMPK）在高糖诱导的细胞损伤中的作用，并探讨了大鼠 INS-1 胰腺β细胞中的相关分子机制。数据表明，栀子苷明显预防了高糖（25 mM）诱导的 INS-1 细胞损伤，这增加了细胞凋亡相关酶的蛋白水平，包括血红素加氧酶-1（HO-1）和 Bcl-2，但明显降低了凋亡蛋白 Bax 的蛋白水平。此外，AMPK 抑制剂 Compound C 显著抑制了栀子苷对 HO-1、Bcl-2 和 Bax 蛋白水平的影响，但 AMPK 激活剂 AICAR 增强了栀子苷对 HO-1、Bcl-2 和 Bax 蛋白水平的作用。更重要的是，栀子苷直接预防了高糖诱导的 caspase-3 裂解，并且在高糖处理的 INS-1 细胞中预先孵育 Compound C 也明显抑制了这种作用。此外，使用 RNA 干扰方法，我们进一步证明用 AMPK siRNA 处理减弱了栀子苷对凋亡相关蛋白和细胞活力的影响。所有这些数据表明，AMPK 在栀子苷拮抗高糖诱导的胰腺β细胞损伤中起关键作用。
